Superconductivity and orbital-selective nematic order in a new titanium-based kagome metal CsTi3Bi5

Abstract

Fabrication of new types of superconductors with novel physical properties has always been a major thread in the research of superconducting materials. An example is the enormous interests generated by the cascade of correlated topological quantum states in the newly discovered vanadium-based kagome superconductors AV3Sb5 (A=K, Rb, and Cs) with a Z2 topological band structure. Here we report the successful fabrication of single-crystals of titanium-based kagome metal CsTi3Bi5 and the observation of superconductivity and electronic nematicity. The onset of the superconducting transition temperature Tc is around 4.8 K. In sharp contrast to the charge density wave superconductor AV3Sb5, we find that the kagome superconductor CsTi3Bi5 preserves translation symmetry, but breaks rotational symmetry and exhibits an electronic nematicity. The angular-dependent magnetoresistivity shows a remarkable two-fold rotational symmetry as the magnetic field rotates in the kagome plane. The scanning tunneling microscopy and spectroscopic imaging detect rotational-symmetry breaking C2 quasiparticle interference patterns (QPI) at low energies, providing further microscopic evidence for electronic nematicity. Combined with first-principle calculations, we find that the nematic QPI is orbital-selective and dominated by the Ti dxz and dyz orbitals, possibly originating from the intriguing orbital bond nematic order. Our findings in the new "135" material CsTi3Bi5 provide new directions for exploring the multi-orbital correlation effect and the role of orbital or bond order in the electron liquid crystal phases evidenced by the symmetry breaking states in kagome superconductors.

References in corpus (5)

• CsV${}_3$Sb${}_5$: a ${\mathbb{Z}}_2$ topological kagome metal with a superconducting ground state
• Superconductivity in the ${\mathbb{Z}}_2$ kagome metal KV${}_3$Sb${}_5$
• Visualizing the Energy-gap Modulations of the Cuprate Pair Density Wave State
• Observation of Flat Band, Dirac Nodal Lines and Topological Surface States in Kagome Superconductor CsTi${}_3$Bi${}_5$
• Screening promising CsV3Sb5-like kagome materials from systematic first-principles evaluation

Cited by in corpus (24)

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• Spectroscopic origin of giant anomalous Hall effect in an interwoven magnetic kagome metal
• Revealing the orbital origins of exotic electronic states with Ti substitution in kagome superconductor CsV3Sb5
• Topological electronic structure and electronic nematicity in candidate kagome superconductors, ATi${}_3$Bi${}_5$ (A = Rb, Cs)
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• Electronic structure of $A$V${}_3$Sb${}_5$ kagome metals
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• Theories for charge-driven nematicity in kagome metals
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• Infrared spectroscopy study of kagome material CsTi${}_3$Bi${}_5$
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• Designing Topological High-Order Van Hove Singularities: Twisted Bilayer Kagomé
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• Odd-parity quadrupole order and induced nonreciprocal transport in the kagome metal CsTi${}_3$Bi${}_5$ driven by quantum interference
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